Many semiconductor devices generate heat during operation which must be dissipated to avoid damage to the device. In some devices, the heat generated is dissipated sufficiently by the enclosure, header or leads. Other devices may be mounted on heat sinks including bodies of thermally conductive materials such as, for example, copper and aluminum which dissipate the heat generated by the semiconductor devices into the surrounding environment. Such heat sinks may be extruded, machined or include sheet metal bodies having heat dissipating fins.
Numerous mounting and fastening devices have been proposed for mounting heat sinks to printed circuit boards, for example, U.S. Pat. No. 4,388,967 issued to L. Breese on June 21, 1983 and entitled "Solderable Mounting Stakes For Heat Sinks"; U.S. Pat. No. 4,403,102 issued to W. Jordan, et al. on Sept. 6, 1983 and entitled "Heat Sink Mounting"; and U.S. Pat. No. 4,054,901 issued to S. Edwards, et al. on Oct. 18, 1977 and entitled "Index Mounting Unitary Heat Sink Apparatus With Apertured Base". Characteristic of these fastening devices is a structure for attaching the heat sink to a printed circuit board or attaching the combination of a semiconductor device and a heat sink to a circuit board in which the fastening device is received by holes formed through the circuit board. The fastener can then be soldered to the bottom surface of the printed circuit board in much the same way other components such as, for example, transistors, resistors and capacitors, are electrically connected to the circuit board such as, for example, wave soldering.
The fabrication of printed circuit boards as well as the assembly process of inserting components through holes in the circuit boards is a costly and time consuming process. It has been proposed that by eliminating the hole mounting requirements for components on printed circuit boards there can be a great reduction in the cost of such printed circuit boards, eliminating hole fabrication and drilling, as well as the labor required to insert components thereon. The surface mounting of components therefore has distinct advantages over present mounting techniques in which the components are inserted through the circuit board for subsequent soldering operations.
The surface mounting of electrical components on printed circuit boards necessitates that heat dissipating devices also be directly mounted to the surface of the printed circuit board to thereby eliminate the need for any mounting holes in the circuit board. A need has thus arisen for surface mounting fastener devices to accommodate the numerous heat dissipating devices used with semiconductor devices.